ASSISTments allows you to download the Assignment Report or Skillbuilder Report data into a .csv file.
Downloading Scores from the Assignment Report
Downloading Scores from the Skillbuilder Report
You will then see and be able to open the file from the download bar at the bottom of your browser or your downloads folder. It will be titled with the date you downloaded in YYYY-MM-DD format (ex: 2020-10-21).